When considering how many cameras you can hook up to your Angelbox, it’s better to think in terms of bitrate capacity than sheer number of cameras (not every camera is built the same).
In terms of bitrate capacity, an AngelBoxes can handle from 20Mbps to 40Mbps of traffic. This means that if you have cameras that each have a bitrate of 1Mbps, then your AngelBox will be able to handle 20-40 of those cameras. Similarly, if your cameras each had a bitrate of 2Mbps, then your AngelBox would handle 10-20 of those cameras.
With that said, this is just an estimation as bitrates tend to vary, especially in the case of variable bitrate settings.
See detailed comparsion: